Power line communication (hereinafter referred to as PLC) has become a popular control technology for the advantage of utilizing existing electric transmission and distribution power lines within buildings or other structures to transmit signals, so the home appliances or network electronic devices are able to be coupled to other networks, such as the Internet, and thus communication or control scheme can be conducted among the networks with devices.
However, when power line communication is applied to control lighting or other kinds of applications, the following issues arise:                1. Low tolerance to interference: the most common interference comes from the noise of devices coupled to power line when power line is used to carry power and carrier signal;        2. High power consumption: generally, the equivalent impedance of an indoor power line system is about 2 to 10 ohms, and a conventional power line communication modem outputs large current in low impedance circumstance, thus causing a high overall power consumption;        3. Low compatibility: the power factor of each of the devices coupled to power line is affected when power line is used to carry power and carrier signal, and thus a current light adjusting circuit or the corresponding devices need to be redesigned before integrated into a power line communication network.        
In view of the above, there is a need for a power line communication AC/DC adaptor that provides higher tolerance to interference, lower power consumption and high compatibility with any existing power line communication network.
In accordance with common practice, the various described features are not drawn to scale and are drawn to emphasize features relevant to the present disclosure. Like reference characters denote like elements throughout the figures and text.